For anybody who isn't sure how to get qemu to emulate the Raspberry Pi in windows here is a zip folder to download.
Just download, extract all the contents and run the extracted run.bat file.
login is pi
password is raspberry
then type startx to get a window based desktop and it is ready to use.
There is a README.txt file for more information. The zip folder contains qemu for windows and the R Pi debian squeeze image. It works in Windows XP. I've only been able to test it briefly in Windows 7, seems to work. Should work in other versions of windows too.
Comments below deal with some issues such as changing keyboard layout.